We construct numerically static non-uniform black string solutions in six dimensions by using pseudo-spectral methods. An appropriately designed adaptation of the methods in regard of the specific behaviour of the field quantities in the vicinity of our numerical boundaries provides us with extremely accurate results, that allows us to get solutions with an unprecedented deformation of the black string horizon. Consequently, we are able to investigate in detail a critical regime within a suitable parameter diagram. In particular, we observe a clearly pronounced maximum in the mass curve, which is in accordance with the results of Kleihaus, Kunz and Radu from 2006. Interestingly, by looking at extremely distorted black strings, we find two further turning points of the mass, resulting in a spiral curve in the black string's phase diagram.
Deformed black strings in 5-dimensional Einstein-Yang-Mills theory
我们在一个5维Einstein-Yang-Mills模型中构造了变形非阿贝尔黑弦的第一个例子。假设所有的场都与额外坐标无关，我们构造了变形黑弦，它在四维图像中对应于引力场理论中的轴对称非阿贝尔黑洞。因此，这些解具有变形的S^2 x R视界拓扑。我们研究了黑弦的基本性质，发现对于所有引力耦合的选择，都存在两个解分支。然而，第二支解的极限行为强烈依赖于引力耦合的选择。
We study string theory with global momentum living on de Sitter space. We also show that this presumption leads to the string with deformed dispersion relation.
Spin chains and classical strings in two parameters $q$-deformed AdS$_3\times$S$^3$
本文研究了Hoare提出的双参数$q$形变AdS $_3\times$ S $^3$中的自旋链和弦激发.我们得到了快自旋极限下的形变自旋链模型，为形变参数的选择提供了依据。详细研究了巨磁振子的一般理论，并对复杂的色散关系作了微扰处理。我们还研究了几种类型的悬弦解，并对它们的电荷和自旋进行了数值分析。最后探讨了它的pp波极限，发现它的解只依赖于变形参数的不同。
Beta Function of k Deformed AdS_5 x S^5 String Theory
我们计算了与q=exp（i pi/k）的量子群相关联的k个变形西格玛模型的世界片上可能的边缘耦合的单圈β函数.这包括玻色子主手征模型和对称空间西格玛模型，也包括k变形半对称空间西格玛模型，它描述了AdS_5 x S^5变形的弦。世界片西格玛模型是规范WZW模型对PSU（2，2）超群的电流-电流变形|4）k级。在弦论中，由于PSU（2，2）的Killing形式为零，β函数为零|4）这是另一个证明k变形理论定义了相容的弦论的证据。
We build string backgrounds for Yang-Baxter deformations of the $AdS_4\times\mathbb{CP}^3$ superstring generated by $r$-matrices satisfying the classical Yang-Baxter equation. We obtain the metric and the NS-NS two-form of the gravity dual corresponding to noncommutative and dipole deformations of ABJM theory, as well as a deformed background with Schrödinger symmetry. The first two backgrounds may also be found by TsT transformations while for the last background we get a new family of non-relativistic ABJM theories with Schrödinger symmetry.
Recently, Arutyunov, Bassi and Lacroix have shown that 2D non-linear sigma model with a deformed $T^{1,1}$ background is classically integrable [arXiv:2010.05573 [hep-th]]. This background includes a Kalb-Ramond two-form with a critical value. Then the sigma model has been conjectured to be non-integrable when the two-form is off critical. We confirm this conjecure by explicitly presenting classical chaos. With a winding string ansatz, the system is reduced to a dynamical system described by a set of ordinary differential equations. Then we find classical chaos, which indicates non-integrabili…
Using a Lorentz invariant deformed string/gauge duality model at finite temperature we calculate the thermal fluctuation and the corresponding linear response, verifying the fluctuation-dissipation theorem. The deformed AdS$_5$ is constructed by the insertion of an exponential factor $\exp(k/r^2)$ in the metric. We also compute the string energy and the mean square displacement in order to investigate the ballistic and diffusive regimes. Furthermore we have studied the dissipation and the linear response in the zero temperature scenario.
We study scalar field and string theory on non commutative q-deformed spaces. We define a product of functions on a non commutative algebra of functions resulting from the q-deformation analogue to the Moyal product for canonically non commutative spaces. We then give the general procedure to define scalar field and classical string theories on the mentioned spaces, we argue that the resulting theories will have enlarged sets of both spacetime and internal symmetries which can be used to study gravitational effects due to the q-deformation.
